Plastic extrusion molding is a process of producing a continuous work piece by forcing molten plastic through a shaped die. As the hot material exits the die the material is carried along a conveyor, cooled, and cut to the desired length. In plastic extrusion molding thermoplastic materials are fed from a hopper into the heated barrel of an extruder. A rotating helical screw inside the barrel pushes the plastic through the barrel toward the die located at the end of the machine. A key advantage of plastic extrusion molding is it’s low cost.
Shapes compatible with extrusion molding are those having a constant cross-section. A few examples of parts often made by plastic extrusion molding include window molding, electronic enclosures, door insulation seals, pipes, rods, etc. The process requires a custom steel die in the shape of the part cross section. Cost reduction options including reducing cross section area, reducing wall thickness and selection of low cost material.
Plastic Extrusion Molding Design Considerations
- Walls must not be too thick to provide cooling.
- Use rounded corners.
- Use uniform wall thickness.
- Long items will have a slight curvature.
- Ends are rough cut.